I recently read the accident report on BEA 548, but I'm unsure of some technical terms used on p. 4 of the report (p. 14 of the linked PDF):
Apart from the probability that in the particular conditions he would have elected to handle the aircraft himself, an examination of the lamp filaments in the P1 'azimuth' window showed that at the time of the crash the compass switch was turned to port, thus indicating that P1 was flying.
My question is: What are the "azimuth window" and "compass switch" in this context? Was the HSA Trident equipped with some sort of flight control transfer system between the P1 (captain) and P2 (flight officer) seats?